1. Field of the Invention
The present invention relates to a combined sensor for almost simultaneously detecting the pressure and the temperature of a fluid, and a flow controller provided with the combined sensor for controlling the flow rate of a fluid flowing through a fluid passage.
2. Description of the Related Art
It is necessary to accurately control the flow rate of a process fluid to be supplied to a processing equipment, for example, in a dry etching apparatus and a thin film-producing apparatus in the process for producing semiconductors. To control the flow rate of the process fluid, a flow controller is arranged in a fluid passage to supply the process fluid to the processing equipment.
The flow controller comprises a pressure sensor for detecting the pressure of the fluid, a temperature sensor for detecting the temperature, and a control valve for controlling the flow rate. Detection signals detected by the pressure sensor and the temperature sensor are introduced into a control circuit in the flow controller respectively. The flow rate of the fluid is calculated based on the detection signal in the control circuit. Thereafter, the flow rate is controlled by adjusting a degree of opening of the control valve depending upon a control signal transmitted from the control circuit to the control valve.
In the conventional flow controller, the pressure sensor and the temperature sensor are arranged separately one by one, and use mutually different detection positions for detecting the pressure and the temperature of the fluid. For the above reason, the following drawback arises. That is, a large space is required for both of the detection positions, and the flow controller itself tends to have a large size. Consequently, a large space is required for installation of the flow controller.
A general object of the present invention is to provide a combined sensor which can reduce the space of the detection positions and realize the miniaturization by closely arranging on an identical surface the detection positions for outputting detection signals corresponding to the pressure and the temperature of a fluid respectively.
A principal object of the present invention is to provide a flow controller which is provided with a miniaturized combined sensor and which can reduce the installation space.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.